/Engine/Source/Runtime/Core/Public/Internationalization/Text.h
Validate the format pattern is valid based on the rules of the given culture (or null to use the current language).
true if the pattern is valid, or false if not (false may also fill in OutValidationErrors).
bool ValidatePattern ( const FCulturePtr & InCulture, [TArray](API\Runtime\Core\Containers\TArray)< [FString](API\Runtime\Core\Containers\FString) > & OutValidationErrors ) const